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  <div id="layout-content"><div id="function.sin" class="refentry">
 <div class="refnamediv">
  <h1 class="refname">sin</h1>
   <p class="verinfo">(PHP 4, PHP 5, PHP 7, PHP 8)</p><p class="refpurpose"><span class="refname">sin</span> &mdash; <span class="dc-title">正弦</span></p>

 </div>
 <div class="refsect1 description" id="refsect1-function.sin-description">
  <h3 class="title">说明</h3>
  <div class="methodsynopsis dc-description">
   <span class="methodname"><strong>sin</strong></span>(<span class="methodparam"><span class="type">float</span> <code class="parameter">$num</code></span>): <span class="type">float</span></div>

  <p class="para rdfs-comment">
   <span class="function"><strong>sin()</strong></span> 返回参数 <code class="parameter">num</code> 的正弦值。参数
   <code class="parameter">num</code> 的单位为弧度。
  </p>
 </div>

 <div class="refsect1 parameters" id="refsect1-function.sin-parameters">
  <h3 class="title">参数</h3>
  <p class="para">
   <dl>
    
     <dt>
<code class="parameter">num</code></dt>

     <dd>

      <p class="para">
       单位是弧度的值。
      </p>
     </dd>

    
   </dl>

  </p>
 </div>

 <div class="refsect1 returnvalues" id="refsect1-function.sin-returnvalues">
  <h3 class="title">返回值</h3>
  <p class="para">
   <code class="parameter">num</code> 的正弦值
  </p>
 </div>

 <div class="refsect1 examples" id="refsect1-function.sin-examples">
  <h3 class="title">范例</h3>
  <p class="para">
   <div class="example" id="example-3109">
    <p><strong>示例 #1 <span class="function"><strong>sin()</strong></span> 例子</strong></p>
    <div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB">&lt;?php<br /><br /></span><span style="color: #FF8000">//&nbsp;返回值的精度由配置中的&nbsp;precision&nbsp;指示确定<br /></span><span style="color: #007700">echo&nbsp;</span><span style="color: #0000BB">sin</span><span style="color: #007700">(</span><span style="color: #0000BB">deg2rad</span><span style="color: #007700">(</span><span style="color: #0000BB">60</span><span style="color: #007700">));&nbsp;&nbsp;</span><span style="color: #FF8000">//&nbsp;&nbsp;0.866025403&nbsp;...<br /></span><span style="color: #007700">echo&nbsp;</span><span style="color: #0000BB">sin</span><span style="color: #007700">(</span><span style="color: #0000BB">60</span><span style="color: #007700">);&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #FF8000">//&nbsp;-0.304810621&nbsp;...<br /><br /></span><span style="color: #0000BB">?&gt;</span>
</span>
</code></div>
    </div>

   </div>
  </p>
 </div>

 <div class="refsect1 seealso" id="refsect1-function.sin-seealso">
  <h3 class="title">参见</h3>
  <p class="para">
   <ul class="simplelist">
    <li class="member"><span class="function"><a href="function.asin.html" class="function" rel="rdfs-seeAlso">asin()</a> - 反正弦</span></li>
    <li class="member"><span class="function"><a href="function.sinh.html" class="function" rel="rdfs-seeAlso">sinh()</a> - 双曲正弦</span></li>
    <li class="member"><span class="function"><a href="function.cos.html" class="function" rel="rdfs-seeAlso">cos()</a> - 余弦</span></li>
    <li class="member"><span class="function"><a href="function.tan.html" class="function" rel="rdfs-seeAlso">tan()</a> - 正切</span></li>
    <li class="member"><span class="function"><a href="function.deg2rad.html" class="function" rel="rdfs-seeAlso">deg2rad()</a> - 将角度转换为弧度</span></li>
   </ul>
  </p>
 </div>

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